Modern conflicts sometimes bring into play chemical or bacteriological munitions enclosing substances that are usually stored in containers. These containers are usually, for evident reasons of security, stored separately from the military charges contained in the cargo vehicle, a missile for example. These substances are manufactured and warehoused in appropriate premises that are sometimes, for strategic reasons, located in the middle of or close to urban zones, populated by civilians. Then, when it is sought to destroy manufacturing and/or storage units, in which noxious substances are warehoused, in containers for example, one of the important preoccupations is to be capable of destroying these units and/or their content without the latter being propagated outside. This is to prevent contaminating the civilians that may be in the vicinity of the building.
In order to destroy storage elements, such as containers, warehoused in a building, use is usually made of perforating projectiles, whose role consists in passing through a wall of said building, usually the roof, so that a destructive charge can penetrate the interior. For reasons of effectiveness, the charge carried by the projectile is distributed, in a known manner, in sub-munitions of smaller size, themselves consisting of bomblets, designed to be thrown in different directions and from different heights, from the point at which the projectile enters the building. Each bomblet then explodes expelling perforating elements, fragments of metal for example, whose action consists in perforating the walls of the containers in order to empty them of their content.
To obtain considerable effectiveness, it is necessary to be able to ensure an optimum dispersion of the bomblets in the storage space of the containers. Furthermore, to be able to ensure the protection of the surrounding populations against the possible risks of contamination, it is necessary that the explosions of the bomblets occur so that the latter destroy the containers without the structure and seal of the building being affected. This control of the effect of the various explosions is the result in particular of controlling the height at which each bomblet or each group of bomblets must be ejected from the projectile payload and the moment of explosion of each bomblet after ejection.
On the one hand, if consideration is given to a projectile whose perforating action is due only to the kinetic energy that it has, it is noted that, according to the nature of the building in question, the impact energy necessary to perforate the roof varies considerably. Specifically, if the target attacked is a production unit, a factory for example, in which individuals are required to spend time during their working hours, the building enclosing the containers is a building of the industrial type whose roof is a thin wall that is easy to pass through. On the other hand, in the case of a storage unit, the user is usually dealing with a structure that is well protected against projectiles, of the shelter type for example whose roof usually consists of a thick concrete slab that usually has no openings.
Then, the problem that is posed, when the user wishes to construct a multipurpose projectile, is associated with the difference of kinetic energy absorption that the projectile sustains depending on whether it is passing through a roof of the industrial building type or a thick roof of the storage building type. Specifically, such a projectile must be able to benefit, at the moment of contact with the wall to be passed through, from a sufficient kinetic energy to be able to pass through the thickest walls. Such a kinetic energy is for example obtained when the projectile comes into contact with the wall, the roof, with a speed of the order of 300 m/s. In this way, when the wall to be perforated is a thick wall, the kinetic energy of the projectile is largely absorbed when passing through. The projectile then continues its course inside the building with a reduced speed which leaves the time to continue with the sequenced ejection of the various bomblets. On the other hand, when the wall to be perforated is a thin wall, such as an industrial building roof for example, the kinetic energy of the projectile is not absorbed by passing through. The projectile then continues its course inside the building at full speed and buries itself very deep in the ground even before the bomblet-dispersion sequence has been able to be controlled and even sometimes applied.
Furthermore, the perforation of the roof of the building enclosing the substances to be destroyed poses a problem of sealing against the outside. Specifically, the dispersed substances may be eminently volatile and therefore be capable of leaving the enclosure that the building constitutes through the penetration orifice, to be dispersed over the neighboring populations.
To solve the problem posed by the speed of penetration of the projectile, an existing solution consists in using less perforating projectiles having for example less weight, and in equipping these projectiles with additional projectiles (mini rockets) capable of destroying the wall, thin or thick, to be passed through. Therefore, the projectile penetrates the building more slowly, which makes it possible to increase the volume reserved for the sub-munitions and to minimize the stresses sustained by the latter. Accordingly, the additional projectiles are fired when the perforating projectile comes close to the wall.
This solution, certainly more costly and more difficult to apply than the solution consisting in using a high kinetic energy projectile, is however overall more effective. On the other hand, it in no way solves the problem of sealing posed by the formation of a hole in the wall or the roof through which the projectile has penetrated the building and neither does it solve the problem associated with an optimal dispersion of the bomblets.